It is known in the prior art to use a carrier to convey envelopes through printing devices. Generally, conventional paper envelopes are attached to a paper carrier sheet with spots of adhesive adjacent to the outer edge of the envelope sealing flap and adjacent to the upper edge of the envelope back panel. An example of such a carrier sheet can be found in U.S. Pat. No. 3,980,006.
Such prior art carrier sheets require special machines to properly position and secure the envelopes to the carrier sheet. Furthermore, another special machine is required to remove the envelopes from the carrier sheet. Consequently, such carrier sheets are not appropriate for use by a low volume mailer, as, for example, many users of personal computers.
In the near future, the United States Post Office may permit application of postage directly on an envelope by a personal computer printer. See the specification issued by the U.S. Postal Service entitled Information Based Indicia Program Postal Security Device Specification ("IBIPPSDS"), dated Jun. 13, 1996. The IBIPPSDS includes proposed specifications for the new information based indicia ("IBI"). The IBI will include a two-dimensional bar code containing hundreds of bytes of information about the mail piece and certain human-readable information. Current U.S. Postal Service IBI specifications require a facing identification mark ("FIM") to be part of the IBI. In the United States, a FIM is a pattern printed in the upper right portion of the envelope adjacent to its top edge. Personal computer systems have difficulty in properly printing the FIM because U.S. Post Office Regulations require precise placement of the FIM near the top edge of the envelope, and the software which controls the printer typically does not permit printing close enough to the edge of the envelope to satisfy the specifications.
Another problem with using a conventional printer to print on an envelope is that such printers have a tendency to cause the glue on the envelope closure flap to adhere to the body of the envelope, thereby sealing or partially sealing the envelope and potentially rendering the envelope useless. Such adhesion is caused by the fact that the closure flap is closed over the body such that the glue contacts the body of the envelope during printing. Heat from the printer causes moisture in the paper to evaporate and moisten the glue which then adheres to the envelope body.